Hi there,
My 1986 Doge ram van 5.2l V8 will cut out uphill and doing 80 on the highway. I have changed the fuel pump, fuel filter, air filter, spark plugs and wires, distributor cap and the alternator. I am running out of options and I was wondering if you could give me any advice?
Many thanks
Tom Harper
Why did you change all those parts? Just to fix the problem? Don’t just throw parts at it hoping it will fix it. Diagnose the problem first.
How about explaining what you mean by “cut out” Does the engine stop running? Will it re-start?
Of does it stumble - run rough and lose power going uphill? If this is true, sounds like a fuel problem. This van still has a carburetor on it, right? Is it the factory carb? Or a replacement? If this is just a stumble going uphill, I’d guess there is junk in the carb’s float bowl or a leak in the carb.
Diagnose first, then replace.
Hi there,
Many thanks for replying. I have recently just bought the van and all those parts had been changed very recently so I had a mechanic look over the parts to make sure they were running ok so I must have worded it wrong. I have been advised that it might take a while to diagnose so trying to avoid spending hundreds of dollars for a diagnosis before I have tried everything I can. The van runs fine but when i put my foot down either up a hill or above 80 on the highway i loose power completely but if i keep my foot down on the highway it will kick back in again. On a hill I stall but if i leave it sitting for a minute or two it will start again. It doesnt run rough with any noises. It cuts out on the highway without any movement but on hills theres stumbling movement when it cuts out but nothing severe. The mechanic advised me about the fuel filter and I have changed quite a few because each time i take them off they are blocked. I have been advised on bad gas but have run methyl hydrate and a full tank of premium gas through it? The carb is a new remanufactured holley and i changed the fuel pump yesterday and it turns out the one i took out wasn’t running at its full capacity. Hope this is a better outline.
Many thanks
Tom
Doubt premium gas would provide any benefits, unless it is pinging on acceleration.
But now that you have used methyl hydrate, I would run a couple of tankfuls of non-ethanol gas through it.
Remove the distributor cap and look for frayed wires. The vacuum advance is constantly adjusting the timing by moving the sensor / pickup. I had that happen on a 1985 car in 1991. When the pickup moved the wires lost contact.
Still sounds like a fuel issue. Trash in the tank based on how many times you have changed the fuel filter. Keep changing it. If it looks like jt has rust in it, you should have the tank removed and a coating applied to the inside to prevent further rusting. Rust will never stop unless you stop it. Change ALL the fuel lines at the same time 'cause 33 year old van.
I’d also suggest your brand new carb needs to be rebuilt to remove the trash your deteriorating fuel system got past the filter.
Sounds to me like it’s time to drop and clean or replace the fuel tank.
Yes we took a fuel sample before it went through the filter and it was full of black sediment but no water. Were booked in to have the tank dropped and flushed out and possibly a new fuel sender if it needs one. The tank is plastic and the specialist thinks that the lining inside has deteriorated and filled the tank with the black sediment. In the mean time the fuel lines are being changed and hopefully that with the new fuel filter, pump and a flushed tank will clean the system out. Like you said dirt could have got through to the carb so that might need to be rebuilt as well. Thank you very much for your help and I will post the outcome on here once we have had the tank flushed etc. Cheers Tom
That’s one of the symptoms of an ignition control module failing.
Tester
I have never known anyone that was successful cleaning out a tank this way. You probably will need a gross of the filters using this approach. I would drain all the gas and drop the tank myself. Then open it and see what you’re faced with…
1986 5.2Lv8 engine configured w/ distributor & electronic ignition w/carb? hmmmm … that was the electronic-controlled carb era, some very difficult to diagnose problems from that era. First off there was a recall on the carb bowl vent adjustment (262T), so double check that’s been done. A carb of that vintage should have a carb rebuild scheduled at some point as a pro-active maintenance measure, but I’d defer that for now. This isn’t a common first symptom for a plugged up carb.
My guess is one of these three
The latter two may be inter-related. When you step on the gas to accelerate the egr activates whatever’s needed to prevent emissions problems and keep the combustion chamber temperature within spec, but when you floor it fully the egr shouldn’t activate. Perhaps instead the egr is fully activating when you floor it.
It could be a problem with the electronic control of the carb’s metering rods too, if that design hosts that function. If not that, then perhaps a problem with the carb’s power valve.
The charcoal canister may have ruptured contaminating the fuel tank with the charcoal particles.
When you clean out the fuel tank be sure to replace the fuel sock for the inlet pipe.
WE HAVE GOOD NEWS!!! our Dodge is all fixed and back on the road running well. In turns out that the previous owner had drilled many screws through the floor of the camper and straight through the fuel tank. In efforts to fix the problem themselves they must have dropped the tank off because the screws have been cut off and their was silicone pumped in to the wholes in the top of the fuel tank. The gas had eaten through the silicone so it was sat at the bottom of the tank and rust and dirt had fallen through the wholes in to the tank as well. The tank has been dropped off and professionally cleaned and repaired including the fuel sender. It was then taken for many test drives and examined by the Repair shop I went to to make sure everything is running the way it should. So we are officially back on the road, thank-you again for all of your comments and helpful advice 
Thanks for the update. I guess the key clue to the diagnosis was every time you changed the fuel filter by visual inspection it appeared to be clogged with gunk. Did the engine run much better immediately after changing the fuel filter and the fuel pump (which presumably has its own in-tank filter)? I mean before they had time to clog up again?
Holes in the top of the gas tank , very unsafe, so it is a double-good thing you got this resolved.
If the previous owner used the type of silicone caulk for sealing homes, that could damage the O2 sensors, just something to be aware of. The type of silicone sealant designed for car engines will say “sensor safe” on the label. Your Dodge may not use any O2 sensors though, being an '86.